<!DOCTYPE html>
<html>
<head>
<script>

function boom()
{
  var c = document.getElementById("c");
  var space = document.createTextNode(" ");
  c.parentNode.insertBefore(space, c);
}

</script>
</head>
<body style="font-family: monospace;" onload="boom();">

<div style="width: 3ch; border: 1px solid orange;">
  <span>a</span> <span>b</span><span id="c">c</span>
</div>

</body>
</html>
